Brake head balancing device



March 10, 1959 c. E. TACK BRAKE HEAD BALANCING DEVICE Filed July 26,1956 1 w k 2 w 0 a I wjw M l 7 k H u 2 1 L i 4 2 WM E M g f m m M w y aw V a t 2 a w 1 2 J a 2 0 J i 1 a 5 K1 3 2 3 6 8 w% w a y 3 fl 2 4 Q H.I/ :5 1 a, W O u. my, (Q g 1 1 n a K 4 W United States Patent 0.

2,876,870 BRAKE HEAD BALANCING DEVICE Carl E. Tack, Chicago, 111.,assignor to American Steel Foundries, Chicago, Ill., a corporation ofNew Jersey Application July 26, 1956, Serial No. 600,272

7 Claims. (Cl. 188-206) My invention pertains to the beamless type ofbrake rigging for railway cars and is particularly concerned with anovel mechanism for applying a braking force to the car wheel andautomatically maintaining the brake head in desired positions relativeto the wheel; such mechanism is commonly known as a brake head balancingdevice.

An object of my invention contemplates the provision of friction meanscapable of automatically maintaining the brake head in an upright spacedrelation relative to the wheel, while the brake is disengaged to preventthe shoe from dragging or binding on the wheel, while also enabling thebrake head to adjust itself relative to the wheel to compensate forwearing away of metal at the braking surfaces.

Another object is to provide an arrangement for preventing dragging orbinding of the brake shoe on the wheel in a case where the hanger leverfor the brake head is pivoted at a point close to the tread of thewheel, for reasons of efiiciency in construction, and in which becauseof such close proximity, such binding may otherwise occur.

Another and specific object is to provide a brake head balancing deviceincluding a hanger lever and balance hanger effectively swingable aboutaxes that are eccentric relative to each other.

A further object is to provide an arrangement of the nature referred toimmediately above in which novel means is included for enabling slidingmovement of the balance hanger to accommodate the guiding movementsthereof.

Another object is to provide safety means for preventing dropping out ofthe balance hanger in the event its connections with operating partsshould for any reason become impaired.

Other objects and advantages of the invention will appear from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

Figure l is a side elevational view of a brake balancing deviceembodying my invention;

Figure 2 is an enlarged sectional view taken on line 2-2 of Figure 1,and

Figure 3 is a partial perspective view of the mountin for the balancehanger. J

Describing my invention in detail and with reference to the drawingsillustrating the mechanism in the engaged position, numeral 2 indicatesahanger lever bracket secured to a railway car truck (not shown) inwhich an axle (not shown) carrying a wheel 4 is'journaledlf Hanger lever6 may be pivotally supported by a pin or bolt and nut assembly 10secured to the bracket 2, the latter having spaced elements embracingthe lever 6. A U-shaped clip 11 is welded to the hanger lever 6 and hasits arms straddling the elements of the bracket 2 and apertured forreceiving the bolt of the bolt and nut assembly 10. The clip improvesthe bearing area and stability of the hanger lever. Brake head 12 isprovided with an opening defined by spaced walls 14-14 and front wall 15Ch f.

for the reception of hanger lever 6 and for the positive limitation ofrotation of brake head 12 relative to hanger lever 6. Brake shoe 13 issecured to brake head 12 for movement therewith.

A hanger lever and brake head of the character herein shown, anddescribed above, are also shown and described in my copendingapplications, Serial No. 241,829, filed August 14, 1951, now Patent No.2,768,713, and Serial No. 584,967, filed May 15, 1956, now Patent No.2,815,102. In each of those two applications mentioned, a balance hangeris incorporated in the assembly and co; operates with the hanger lever 6in control and operation of the brake head. In the present instance, thebalance hanger 8 of novel construction constitutes an essential part ofthe invention and will bedescribed in detail here* inbelow. However, inaddition to its novel features, it also cooperates with the hanger lever6 in control of the brake head by friction means, as in the abovementioned applications. The latter control is brought about throughfriction engagement between the balance hanger and the brake head. Thebalance hanger in the present instance, designated as 8, includes aplate portion 9 spaced from the hanger lever 6 in the direction of theaxis of the pin 10 and extends downwardly to the lower end of the hangerlever. Helicalsprings 16-16 sleeved around lugs 18-18 are interposedbetween wall 14 and balance hanger 8, the springs being seated in flatface abutment. Hanger lever 6, balance hanger 8, brake head 12 andsprings 16-16 are secured in assembled relation by a bolt and nutassembly 20. This arrangement afiords spaced supporting bearings for thebolt of bolt and nut assembly 20, retains springs 16-16 in a compressedor loaded condition, and affords pivotal movement of brake head 12relative to its axis against the frictional resistance developed at A,B, C and D, as hereinafter more fully described. Bushings affordingbetter wearing surfaces are provided in every pivotal connection as at22, 22, 24, 27, 27, 28, 28, 30 and 32. The bushing 27 at one end, e. g.,adjacent the nut on the bolt and nut assembly, may be rubber, as shown,to take up play.

The operation or function of the assembly from the standpoint offriction control of the brake head, as mentioned above, is as follows:

The forces exerted by compressed springs 16-16 cause the members tofirmly frictionally engage each other at A, B, C and D to maintain brakehead 12 in a substan tially upright position while the brake isdisengaged; as a result of any turning moment exerted on the brake headthe flat ends of springs 16-16 will tend to slide on balance hanger 8 atA and B, the brake head will tend to slide on the washer at C, and thebolt head will tend to slide on the balance hanger at D. This sliding isresisted or checked by the frictional moments automatically developed atA, B, C and D. Consequently, the brake head will normally not rotateunder the influence of its weight, vibrations and impacts but willremain in an upright position to readily facilitate braking. The forcesexerted by compressed springs 16-16 on the brake balancing device act toprevent rattling and damaging vibrations.

The brake is applied and released by appropriate forces at the upper endof the brake lever in Figure 1 as per arrows 34, the full line arrowindicating direction of application, and the dotted line arrow thedirection of release. The hanger lever is pivoted about the pin 10 asnoted above, and it will be noted that this pin is so located that aline drawn between the axis thereof and the axis of the wheel 4(Figure 1) is below the upper end of the brake shoe. Hence, were it notfor the provision to prevent it, the upper end of the brake shoe wouldhind on the wheel tread surface in applying and releas ing the brake. Ifthe brake shoe remained fixed relative to the hanger lever, such bindingeffect would take place Patented M83310, 1959 in the swinging movementsof the lever. However, this binding effect is prevented by the novelbalance hanger of the invention.

The balance hanger 8 is pivotally mounted on the bolt 20 and has an arm35 extending upwardly to and through the bracket assembly 36. Thisassembly includes suitable frame members 38 (Figure 3) secured to thetruck at a suitable location such as 40 and has a pair of spacedresilient pieces or blocks 42 therein. These resilient pieces arepreferably of rubber or rubber-like composition having the desiredresilience characteristics. The hanger lever extends between theserubber blocks and is quite tightly gripped thereby. A cross piece 37 issecured to the upper end of the balance hanger as a safety measure toprevent the balance hanger from dropping out of its connections to otherelements should the connections thereto for any reason be disabled.

The operation of the balance hanger in preventing binding of the brakeshoe with the wheel is as follows: For convenience, the description ofthe operation of the device will be given in connection with release ofthe brake. In this operation, the hanger lever 6 is rotatedcounterclockwise (Figure l). A tendency exists for the balance hanger tobe moved in the same direction, namely, rotated counterclockwise. Insuch movement, the upper end of the balance hanger would move to theleft (Figure l), but it is prevented from so doing by the bracketassembly 36. The net result is that the balance hanger, relative to thehanger lever, swings clockwise, and since the brake shoe is mounted tothe balance hanger for rotating therewith about the axis of the bolt 20,as explained in the above applications, it will itself move or rotateclockwise, at least relatively speaking. Hence, as the hanger levermoves the brake head away from the wheel, the relative clockwisemovement of the brake head results in the brake shoe remainingapproximately parallel with the wheel tread.

The distance between the pivot axis of the bolt 20 and the effectiveconnection between the balance hanger and the bracket 36 should begreater than the distance between the pivot axis of the brake lever 6,at 10, and the axis at 20. The greater this dilference in distance, thegreater will be the clearance of the brake shoe relative to the wheeltread and hence as a practical matter that connection is placed at arelatively great height.

The resiliency afforded by the rubber blocks 42 accommodates inaccuracyin the parts and results in smoother and more resilient action. Therelatively great gripping action by the rubber blocks prevents thebalance hanger from unduly shifting about. The connection between thebalance hanger and the rubber blocks may be considered as a pivotalconnection in that the balance hanger swings about the blocks as afulcrum.

This connection also permits longitudinal sliding movement of thebalance hanger to accommodate the movements of the brake head madenecessary by the difference in efiective lengths of the balance hangerand hanger lever.

I claim:

l. A brake head balancing device for a railway car truck comprising ahanger lever pivotally connected to said truck, a brake head pivotallymounted on said lever, and a balance hanger connected to said brake headand to said truck at a point on the latter eccentric to the pivot axisof the hanger lever, said balance hanger being permitted limited lateraland longitudinal movement relative to the truck, said point being spacedfrom thecon- 4 nection point between the balance hanger and brake h ad adi tance reate than the dis an e b n the pivot axis of the hanger leverand the connection between the latter and brake head.

2. A brake head balancing device for a railway car truck comprising ahanger lever pivotally connected to said truck, a brake head pivotallymounted on said lever, a balance hanger connected to said brake head, aconnection between said balance hanger and the truck for allowing saidbalance hanger to move longitudinally and laterally relative to thetruck, the connection between the hanger and the truck being located ata point on the latter eccentric to the pivot axis of the hanger lever,and a frictional connection between the balance hanger and brake head.

3. A brake head balancing device for a railway car truck comprising ahanger lever pivotally connected to said truck, a brake head and a pinpivotally connecting it to said hanger lever, a balance hanger pivotallyconnected to said pin, friction means interposed between said brake headand balance hanger, and a connection between said balance hanger andtruck for allowing said balance hanger to move laterally andlongitudinally relative to the truck.

4. A brake head balancing device for a railway car truck comprising abrake head, a hanger lever, means to fulcrum said hanger lever, abalance hanger, means pivotally connecting said brake head to saidhanger lever and to said balance hanger, a frictional connection betweenthe balance hanger and the brake head operable to resist relativepivotal movement therebetween, and a connection between said balancehanger and the truck spaced from said fulcrum means for allowing saidbalance hanger to move longitudinally and laterally relative to thetruck.

5. A brake head balance device according to claim 4, wherein theconnection between the balance hanger and the truck includes resilientmeans on the latter defining an opening within which the former issnugly received.

6. A brake head balancing device for a railway car truck comprising abrake head, a hanger lever, means to fulcrum said hanger lever, abalance hanger, means pivotally connecting said brake head to saidhanger lever and to said balance hanger, a frictional connection be.-tween the balance hanger and the brake head operable to resist relativepivotal movement therebetween, and a connection between said balancehanger and the truck spaced from said fulcrum means, the connection be.-tween the balance hanger and the truck including resilient meansfrictionally gripping said balance hanger.

7. A brake head balancing device for a railway car truck comprising abrake head, a hanger lever, means to fulcrum said hanger lever, abalance hanger, means pivotally connecting said brake head to saidhanger lever and to said balance hanger, a frictional connection betweenthe balance hanger and the brake head operable to resist relativepivotal movement therebetween, and a connection between said balancehanger and the truck spaced from said fulcrum means, the connectionbetween the balance hanger and the truck including a cross piece secured.on said balance hanger and a bracket on the truck engageable with saidcross piece and operable as stop means for said cross piece.

References Cited in the file of this patent UNITE TATE PA E TS

